Approximately 40% of older adults in clinical practice will experience varying degrees of oral dryness. Dry mouth is generally considered to be caused by both disease-related and medical causes. Dry mouth can cause poor denture retention, meaning that some older adults feel uncomfortable wearing their denture. Dry mouth can also cause poor denture insertion, difficulty chewing and swallowing, and increase the chance of denture and oral mucosal infection. When dry mouth, the oral mucosa becomes more fragile and more sensitive to chemical stimulation, which can easily induce oral candidiasis, as well as retrograde salivary adenitis, furrowed tongue and dry tongue mucosa. In addition, dry mouth in the elderly is related to mouth breathing. Some elderly people complain of dry mouth, but there is no corresponding etiology in clinical examination or examination of medical history, and this condition may be related to mental depression. The main treatment of dry mouth is to prevent further salivary reduction, in addition to smoking cessation, mouth breathing correction, alcohol cessation, and discontinuation of anticholinergic drugs, the etiology can also be treated. If the secretory function is still possible, salivary secretion can be stimulated by changing the medication, such as telling the patient to contain vitamin C to stimulate salivary gland secretion and relieve dry mouth symptoms, or telling the patient to bring a glass of water with him when he visits the clinic and to bring it with him wherever he goes. Taste stimulants such as citric acid and malic acid containing preparations can also be used. For patients who have only a very small amount of salivary secretion function left, substitutes for saliva should be given, such as for viscous saliva or high or low viscosity saliva, preparations such as saline or high viscosity liquid paraffin that can relieve saliva should be given.